1. Field of the Invention
The present invention relates to a liquid container, and more particularly to a knock-type liquid container that holds a liquid such as cosmetic liquid, writing ink, or correcting liquid and has a liquid outlet provided at a tip portion of the container.
2. Description of the Related Art
A conventional liquid container that holds the above-mentioned type of liquid is disclosed in Japanese Patent Application (JPA) No. 2000-51919 applied for by the inventors of the present application.
This conventional knock-type liquid container aims to supply the liquid therein forwardly of the container by a user""s knocking operation, and includes a tank, a piston, a threaded rod, a rotating cam, a knocking cam, and a knocking body. The tank holds a liquid therein and has a liquid outlet provided at the forward end thereof. The piston slides in the tank.
The threaded rod, integrally formed with the piston, extends rearwardly of the piston and has a male thread on its outer circumferential surface. The threaded rod is not rotatable relative to the tank. The rotating cam has a female threaded hole into which the male thread of the threaded rod is screwed. The knocking cam is disposed rearwardly of the rotating cam and causes the rotating cam to rotate in one direction. The knocking body is resiliently urged rearwardly relative to the knocking cam and is operated to perform a knocking operation. One of the knocking body and the knocking cam has a projection formed thereon and the other of the knocking body and the knocking cam has a beveled path that inclines in the axial direction and fittingly receives the projection. Knocking the knocking body causes the knocking cam to rotate, thereby causing the rotating cam to rotate.
This configuration allows the liquid to be supplied by a knocking operation of the knocking body. The configuration is advantageous in that the knocking operation requires only a one-hand operation, thereby providing good operability.
However, because of the simple nature of the knocking action, the knocking body may be knocked inadvertently, thereby causing the piston to advance forwardly to discharge the liquid from the tank. Therefore, conventionally, to prevent the knocking body from being inadvertently knocked, the force required to knock the knocking body should be sufficiently large (e.g., about 12.7 N=1.3 kg weight). However, such a relatively large force impairs the operability of the knocking body. This is a problem.
In view of the foregoing and other problems, drawbacks, and disadvantages of the conventional structures, an object of the present invention is to provide a liquid container in which even if a knocking body is knocked inadvertently, the liquid in the container is prevented from being discharged.
To attain the aforementioned and other objects, in an exemplary, non-limiting embodiment, a knock-type liquid container according to the present invention includes a body having a tank that holds a liquid therein and an outlet provided at a forward end, a piston in the tank, and a piston-advancing mechanism having a knocking body that projects rearwardly of the body for advancing the piston in the tank forwardly when the knocking body is knocked in an axial direction of the liquid container. A rear end of the liquid container, except for the knocking body, has a surface making an angle other than a right angle with the axial direction.
Hence, when the knocking body is inadvertently knocked by surroundings and the rear end of the knocking body is moved toward the liquid container (except the knocking body) until the rear end of the knocking body is flush with the rearmost portion of the rear end of the liquid container (except the knocking body), the knocking body is unable to move any further into the liquid container. Hence, the knocking body is prevented from being knocked at a most completely forward position in the axial direction. This prevents the piston from being advanced forwardly, thereby preventing unwanted discharge of the liquid through the liquid outlet of the body. When the user attempts to push the piston to discharge the liquid, he can discharge the liquid by knocking the knocking body into the container further than the rearmost portion of the rear end of the liquid container (except the knocking body).
When the knocking body is at a non-knocking position, a distance in the axial direction between a rear end surface of the knocking body and a rearmost portion of the rear end of the liquid container (except the knocking body) can be selected to be equal to or less than a stroke of the knocking body required for advancing the piston. Thereby, the rear end of the knocking body is knocked into the liquid container until the rear end of the knocking body is flush with the rearmost portion of the rear end of the liquid container (except the knocking body), and the piston is unable to advance any further. Thus, the liquid can be prevented from being discharged forwardly of the liquid outlet.
The piston-advancing mechanism can include a piston rod having a front end coupled to the piston, extending rearwardly of the piston, having a male thread on an outer circumferential surface thereof and prevented from rotating with respect to the tank, a piston rod guide having a female-threaded hole on a front inner circumferential surface, the female-thread hole receiving the male-threaded piston rod screwed thereinto, an inner sleeve into which the piston rod is unrotatably inserted, a rotating cam unrotatably mounted around an outer circumferential surface of the piston rod guide, the knocking body, a rear cap that includes a rotating cam mechanism together with the rotating cam and the knocking body, and a return spring that urges the rotating cam rearwardly.
The rotating cam mechanism converts an amount of knock of the knocking body into an amount of rotation of the rotating cam. Hence, when the knocking body is knocked, the rotating cam mechanism converts knocking of the knocking body into rotation of the rotating cam, so that the piston rod guide rotates. Because the male-threaded piston rod that is screwed into the female-threaded hole of piston rod guide cannot rotate relative to the tank, the piston rod advances so that the piston is pushed forwardly. The rotating cam mechanism allows for some xe2x80x9cplayxe2x80x9d (e.g., delay) from the knocking of the knocking body until the rotating cam actually rotates, so that an inadvertent knocking does not cause the piston to advance forwardly by utilizing the play.
The piston-advancing mechanism can include a piston rod having a front end coupled to the piston, extending rearwardly of the piston, having a male thread on an outer circumferential surface thereof and prevented from rotating with respect to the tank, a rotating cam having a female threaded hole receiving the male thread of the piston rod screwed thereinto, a ratchet sleeve through which a piston rod extends, the ratchet sleeve being fixed forwardly of the rotating cam in the tank, a knocking cam that is positioned rearward of the rotating cam and can rotate the rotating cam, the knocking body, and a knock spring that is disposed between the knocking cam and the knocking body and resiliently urges the knocking body rearwardly.
One of the knocking body and the knocking cam has a projection formed thereon and the other of the knocking body and the knocking cam has a beveled path that inclines in the axial direction and fittingly receives the projection. The rotating cam has a front end with saw-teeth formed thereon and the ratchet sleeve is formed with a ratchet tooth that can mesh with the saw-teeth formed on the rotating cam and is movable to extend and retract in the axis direction. When the knocking body is knocked, the projection formed on one of the knocking body and the knocking cam moves in the beveled path formed on the other of the knocking body and the knocking cam, so that the knocking cam rotates and therefore the rotating cam rotates.
Because the male-threaded piston rod that is screwed into the female-threaded hole of the rotating cam cannot rotate relative to the tank, the piston rod advances so that the piston is pushed forwardly. There is some play before the saw-teeth of the rotating cam overrides the ratchet tooth of the ratchet sleeve. This play is utilized to prevent the piston from advancing forwardly when the knocking body is inadvertently knocked.